public class circleTest {
    public static void main(String[] args) {
        circle circle = new circle();
        circle.r = 220;
        circle.area ();
        double pai = 3.1415926;
        double s = circle.area2(pai);
        System.out.println("半径为："+ circle.r +"的圆，面积为："+ s);
    }
    }
